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Date:   Wed,  9 Dec 2020 19:24:16 +0100
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Subject: [PATCH mm 2/2] Revert "kasan, arm64: don't allow SW_TAGS with ARM64_MTE"
From:   Andrey Konovalov <andreyknvl@google.com>
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Marco Elver <elver@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>
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Precedence: bulk

This reverts "kasan, arm64: don't allow SW_TAGS with ARM64_MTE".

In earlier versions on the hardware tag-based KASAN patchset in-kernel
MTE used to be always enabled when CONFIG_ARM64_MTE is on. This caused
conflicts with the software tag-based KASAN mode.

This is no logner the case: in-kernel MTE is never enabled unless the
CONFIG_KASAN_HW_TAGS is enabled, so there are no more conflicts with
CONFIG_KASAN_SW_TAGS.

Allow CONFIG_KASAN_SW_TAGS to be enabled even when CONFIG_ARM64_MTE is
enabled.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 arch/arm64/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6fefab9041d8..62a7668976a2 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -135,7 +135,7 @@ config ARM64
 	select HAVE_ARCH_JUMP_LABEL
 	select HAVE_ARCH_JUMP_LABEL_RELATIVE
 	select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
-	select HAVE_ARCH_KASAN_SW_TAGS if (HAVE_ARCH_KASAN && !ARM64_MTE)
+	select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
 	select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE)
 	select HAVE_ARCH_KFENCE
 	select HAVE_ARCH_KGDB
-- 
2.29.2.576.ga3fc446d84-goog